A system and method for displaying plug-in supplied content in a browser-embedded window is provided. A plug-in module supplies content to a host application for display in a browser-embedded window. The plug-in supplied content contains special tags which identify certain processing actions to be taken by the host application on the content prior to display. The special tags in the content relieve the plug-in module from modifying its content upon installation according to the installation location of the host application. The special tags identify references, images, and controls. The control tags enable the plug-in module to receive event messages from controls embedded in the content that are manipulated by a user in the browser-embedded window. The plug-in modules implement a well-defined set of callback routines for receiving the event messages.